The creep property of cement grouted joint is studied based on creep test and theoretical analysis. Firstly, the multi-stage shear creep test under constant normal stress, joint roughness and cement filled thickness is carried out to obtain the creep deformation. Then the conventional linear Nishihara model is used to fit the test results. Due to the big deviation of the theoretical results from the test, the instantaneous elastic shear stiffnesses under different loading stages are calculated. It is found that they vary with the shear stress. The reasons for the nonlinearity are analyzed. Finally the parameters of the Nishihara model are modified to be nonlinear and fit with the test results showing good coincidence between them. These researches release the creep property of the cement grouted joint, and will provide a good basis for further research considering more influencing factors such as normal stress, joint roughness and cement filled thickness.